I am trying to create a Django queryset that returns records in a specific order that matches a list of IDs.
我正在尝试创建一个Django查询集,该查询集以特定顺序返回与ID列表匹配的记录。
My list of IDs is:
我的ID列表是:
[34,12,4,89,3,67,11]
If I run the following query:
如果我运行以下查询:
queryset = Item.objects.filter(pk__in=[34,12,4,89,3,67,11])
The query returns records in the ID order:
查询以ID顺序返回记录:
3,4,11,12,34,67,89
Is there any way to make the query return the records in the same order as the list?
有没有办法让查询以与列表相同的顺序返回记录?
If not is there a way to re-order the query result into the required order?
如果没有,是否有办法将查询结果重新排序为所需的顺序?
1 个解决方案
#1
1
Note: Adding this as an answer because OP asked about the approach in the comments of the original question. Showing the snippets in comments didn't allow fenced code blocks.
注意:添加此作为答案,因为OP询问了原始问题的评论中的方法。在注释中显示片段不允许使用受防护的代码块。
In the comments on the original question, I mentioned an alternative solution storing your order numbers in a model field, so that ordered queries would be simpler.
在对原始问题的评论中,我提到了一种替代解决方案,将您的订单号存储在模型字段中,以便有序查询更简单。
One use case for this is if you have a queue of objects where each item is a movie and the user is deciding which order to watch them. You might want to let a Django admin or a user re-order the items (hence making it a field). For the sake of a simple example let's assume there is only one user so we'll build the ordering into the model, as opposed to making a custom table to join through Item and User models.
一个用例就是如果你有一个对象队列,其中每个项目都是一个电影,用户正在决定观看它们的顺序。您可能想让Django管理员或用户重新订购项目(因此将其作为字段)。为了一个简单的例子,我们假设只有一个用户,因此我们将在模型中构建排序,而不是通过Item和User模型建立自定义表。
The model:
class Item(models.Model):
# ...
my_order = models.PositiveIntegerField(unique=True)
Set the attribute either at creation or later:
在创建时或以后设置属性:
Item.objects.create(id=34, my_order=1)
Item.objects.create(id=12, my_order=2)
Item.objects.create(id=4, my_order=3)
# ...
Of course, you could create them and set my_order in any order you wished, and the result will still be the same.
当然,您可以按照您希望的任何顺序创建它们并设置my_order,结果仍然是相同的。
Retrieve the objects in desired order:
按所需顺序检索对象:
queryset = Item.objects.order_by('my_order')
#1
1
Note: Adding this as an answer because OP asked about the approach in the comments of the original question. Showing the snippets in comments didn't allow fenced code blocks.
注意:添加此作为答案,因为OP询问了原始问题的评论中的方法。在注释中显示片段不允许使用受防护的代码块。
In the comments on the original question, I mentioned an alternative solution storing your order numbers in a model field, so that ordered queries would be simpler.
在对原始问题的评论中,我提到了一种替代解决方案,将您的订单号存储在模型字段中,以便有序查询更简单。
One use case for this is if you have a queue of objects where each item is a movie and the user is deciding which order to watch them. You might want to let a Django admin or a user re-order the items (hence making it a field). For the sake of a simple example let's assume there is only one user so we'll build the ordering into the model, as opposed to making a custom table to join through Item and User models.
一个用例就是如果你有一个对象队列,其中每个项目都是一个电影,用户正在决定观看它们的顺序。您可能想让Django管理员或用户重新订购项目(因此将其作为字段)。为了一个简单的例子,我们假设只有一个用户,因此我们将在模型中构建排序,而不是通过Item和User模型建立自定义表。
The model:
class Item(models.Model):
# ...
my_order = models.PositiveIntegerField(unique=True)
Set the attribute either at creation or later:
在创建时或以后设置属性:
Item.objects.create(id=34, my_order=1)
Item.objects.create(id=12, my_order=2)
Item.objects.create(id=4, my_order=3)
# ...
Of course, you could create them and set my_order in any order you wished, and the result will still be the same.
当然,您可以按照您希望的任何顺序创建它们并设置my_order,结果仍然是相同的。
Retrieve the objects in desired order:
按所需顺序检索对象:
queryset = Item.objects.order_by('my_order')